William e



- WILUA'M E PRALLQ lmprovement'in Fire Extinguishers fer Steam Boilers.

No. 122,489. Patentedlan.2,1872

yfltmssw AM. PHUTO-ITHOGRAPHIC C0. 11). OSBORNE? P17965554 Unrrnn S'rA'rns WILLIAME. PRALL, OF WASHINGTON, DISTRICT OF COLUMBIA.

IMPROVEMENT IN FIRE- EXTBNGUISHERS FQR STEAM-BOILERS.

Specification forming part of Letters Patent N 0. 122,489, dated January 2, 1872.

Specification describing certain Improvements in Fire-Extin guishers for Steam-Boilers, invented by WILLIAM E.PRALL,OfWaiSl1ington, District of Columbia.

The object of this invention is to prevent explosions of steam-boilers from the scarcity of water.

I am aware that many-devices have been made for that purpose, but from their complication anduncertain ty of operation have proved unreliable, and those devices which are intended to give an alarm or start the supply of water into the boiler are very apt to increase the negligence of engineers, and if from any cause, asdrunkenness or absence, he could not give his attention, an explosion might be the result.

r This device, which is verysimple in its construction and positive in its operation, removes all danger independent of the action of the cast with it, in which is placed a weight or spring, whichrests with its force upon the upper side of thediaphragm. A balance-valve, G, or some other suitable valve is attached to the lower side of the diaphragm-case, the stem ofwhich is connected to the flexible diaphragm. In the drawing I have shown a valve so constructed that the steam or water can pass around it and come in contact witlrthe diaphragm in a manner which will permitthe' pressure to be exerted alike on both sides from the connecting-pipes. A dischargepipe, F, is connected with the valve-chamber and extended to the furnace, and is so arranged that when the valve isopen the steam or water will be forced from the boiler and extinguish the fire. It is evident that many different arrangements of the flexible diaphragm could be made which would produce the same movement and communicate it to some kind of a cut-off, which would permit the escape of the steam or water into the furnace. With a full knowledge of this, I do not confine myself to the particular arrangement shown. The fire could be very much reduced by connecting a rod from the diaphragm with a damper, which would shu off the draught.

I will now describe the operation of this device more particularly. The diaphragm is placed a short distance above the water level in the boiler, as shown in Fig. 1. One leg of the pipe is connected with the boiler at a point where it is safe for the water to be lowered, but below which it is desired it should not reach; theother leg is conducted a few inches below that point, where it enters the boiler also. The pipe which connects with the valve chamber is conducted to the fire-chamber, and that portion of it which enters the furnace may be perforated so as to distribute the steam or water over the entire fire-space. When the boiler is filled and ready for action both ends ofthe diaphragm-pipes are under water, and whenthe pressure is created by steam the water will be driven up in both pipes and fill them and the diaphragm-case, the air in them will soon be absorbed, or it may be allowed to escape through a cock at the top. The press ure from within the boiler will press equally on both sides of the diaphragm, and an equilibrium will exist, the diaphragm and valve stem connected to it will be forced down by the weight placed on the upper side, and the valve which controls the escape of steam or water will be closed and remain so as long as both ends of the pipes are under water; but

should the water from any cause be permitted to recede below the upper or short leg the water will run out of it and steam will take its place. The effect will be to increase the pressure on that side of the diaphragm with which it connects equal to the weight of the column of water-withdrawn on the entire surface. of

the diaphragm. This gives an abundance of power to force thediaphragm upward, which will open the exhaustvalve and permit the- Parana marten.

Thecombination of the diaphragm operated by the intermittent column of Water and under pressure on both sides, the exhaust-valve 0perated by the movement of the diaphragm, and the pipe connecting the valve-opening with thefurnace of a steam-generator, as shown and described.

W. E. PBALL.

Witnesses: EDM. F. BROW'N,

J. R. NOTTINGHAM. (148) 

